I’m not sure if Solbyeongsan deserves a post separate from Aengsan, but it’s technically it’s own mountain with it’s own summit, so here ya go.
Solbyeongsan is a sister mountain to Aengsan, sharing most of the same path. To get to the peak follow the trailhead directions for Aengsan and turn left at the clearing. It’s only 0.2km from the clearing area up a steep hill. There are no views from the summit, BUT there is perhaps one of the cutest homemade summit markers I’ve seen.